Blueback \Blue"back`\, n. (Zool.)
(a) A trout (Salmo oquassa) inhabiting some of the lakes of
Maine.
(b) A salmon (Oncorhynchus nerka) of the Columbia River and
northward.
(c) An American river herring (Clupea [ae]stivalis),
closely allied to the alewife.
[1913 Webster]